Like many brides-to-be, Caitlin O Connor fantasized about the gown that would make everyone ooh and ahh as she walked down the aisle. In fact, she was about to drop more than $6,000 for the one when her fianc reminded her of one little detail: They were paying for the wedding themselves.

After he half-jokingly suggested she try Goodwill, the 26-year-old Denver-based account manager lucked out and found the exact same dress okay, one size bigger for half the original price. But it wasn t at a designer sample sale or a high-end wedding-boutique clearance. Instead, O Connor had Googled the designer s name and the word used and found the frock on PreOwnedWeddingDresses.com.

Forget Mom s heirloom gown and Grandma s resized wedding ring. A surprising number of couples are dressing up their big day with secondhand stuff from total strangers, much of it bought online. As the sputtering economy continues to drive nuptial expenditures down the average wedding cost in 2009 dropped 10 percent from 2008, according to research firm The Wedding Report budget cutting has gone beyond slashing guest lists and downgrading to a deejay.

In recent years legions of new Web sites have appeared, hawking cast-off gowns, recycled rings and more. Sales at PreOwnedWeddingDresses.com jumped 169 percent in 2009, while those at IDoNowIDont.com more than tripled in the same period. Indeed, today s couples, many of whom are children of divorce, are less apt than ever to see their bride-and-groom gear as lasting treasures, says Ruben Cruz, bridal designer and professor at the Fashion Institute of Technology. The ceremony is a four-hour deal, and then what?

A recent GetMarried.com But while even intrepid bargaineers might understandably balk at buying a pricey diamond or gown online, more couples say they re open to integrating other people s castoffs into their big day.

Of course, not many betrothed envision vowing Till death do us part with a spurned lover s ring. And few little-girl wedding fantasies involve someone else conga-line dancing in the dress first. But these days, as couples feel the pinch of tighter credit and iffier job prospects, symbolic stigmas are melting away in the face of tangible savings.

Retail markup on engagement rings can run as high as 300 percent, says Antoinette Matlins, a gemologist and the author of more than half a dozen jewelry-buying guides. That makes deals like the bauble one buyer recently snagged on IDoNowIDont.com for $700 and later had appraised for $4,600 all the more compelling. Mara Opperman, cofounder of the site, says its average transaction price is $2,500, usually 30 to 60 percent below retail.

And with designer-gown hunters choking on four-figure price tags (wearing a $7,000 gown for six hours translates to nearly $20 a minute), it s no wonder hand-me-downs are gaining favor. Sites like e-boutique EncoreBridal.com and direct peer-to-peer listing sites like BravoBride.com say they regularly move frocks for more than half off.

And the deals aren t limited to big-ticket items. Popular online communities like TheNest.com and Weddingbee.com feature trading boards where future and former brides haggle over everything from tiaras and flower-girl baskets to aisle runners and crystal centerpieces. One bride-to-be even advertised 125 champagne flutes on TheNest.com s Trash to Treasure community board four months before the actual event. Her reasoning? There s no use for them after the wedding day.

That is, unless they can take on a higher purpose than just cluttering the attic. That s why some sites pitch their secondhand goods as earth-friendly whether it s reducing the need for new diamond mining or cutting carbon emissions by not adding demand to the $60 billion wedding-product industry. Doing good for the environment not reason enough? A few vendors also boast doing good for others: BravoBride.com donates a portion of its listing-fee proceeds to the American Heart Association, while OnceWed.com shares revenue with the International Justice Mission.

Of course, the feel-good factor might take a hit if a bride learns that her designer dress is a cheap knockoff or a groom-to-be discovers that the rock he saved for is low-grade, lab-enhanced or gulp cubic zirconia. Many nuptial experts still counsel steering clear of buying pricey items online, sight unseen; to protect a Web purchase, they recommend asking for receipts from the original purchase and using only sites that offer escrow services so goods can be inspected before payment.

Indeed, say industry watchers, both designer labels and the all important diamond-grading certificates that detail a stone s individual characteristics are sometimes cleverly forged. IDoNowIDont.com, for one, pays a third-party gemologist to ensure that rings being offered actually live up to their advertised color, clarity and carat count. If one s not available, says Matlins, the safest move is to pay for an independent appraisal. Because ideally, once purchased, that ring won t be going on the market again.